M24 Light Tank Chaffee

Background
Development
Description
Combat
Variants
Stats

Background

The M24 Chaffee Light Tank was the best light tank to see service during the Second World War, but it arrived too late to make a significant contribution to the fighting, entering combat in small numbers late in 1944.

American troops first entered combat against the Germans after the start of Operation Torch, the invasion of North Africa of November 1942. The Germans rushed troops and tanks to Tunisia, and the resulting campaign lasted until May 1943. At the start of this campaign the US Armored Force had expected the M5 Light Tank to be able to operate alongside the newer medium tanks, playing a major part in the main battle. It quickly became clear that the M5 was very vulnerable to the German anti-tank weapons that accompanied their infantry. This meant that it struggled to carry out reconnaissance, as there was a real danger that the scouting tanks would be destroyed by the very troops they had been sent to find. They were hopelessly outclassed by the German tanks of 1943, and most of the senior tank commanders who fought in Tunisia wanted the M5 to be withdrawn and replaced with a more heavily armed and armoured tank. Patton and Bradley supported this idea, and wanted the M5 limited to a reconnaissance role. In the aftermath of the Tunisian campaign the US Army got rid of most of its light tank battalions, and instead created a force of mixed battalions, with three companies of medium tanks and one company of light tanks.

The expectation that the light tank would be able to act as an infantry support weapon, and take part in exploitation of breaks in the German lines played a part in the failure of the T7 Light Tank/ M7 Medium Tank. Work on the T7 began in January 1941, when it was to be 14 ton tank, armed with a 37mm gun. It soon became clear that this gun was no longer effective, and in 1942 the design was altered, first to use a 57mm gun and then a 75mm gun. By this time the tank had expanded so much that in August 1942 it was standardised as the M7 Medium Tank. A handful of M7s were completed before the project was cancelled in February 1943. The problem was this tank had been designed for a role that the light tank could no longer hope to carry out in the face of modern anti-tank weapons. In an attempt to produce a tank that could indeed survive on the battlefield of 1942 the T7 light tank had evolved into a medium tank, leaving the M5 to fight on.

An attempt was made to mount the 75mm gun on the M5 chassis. This used a modified turret from the M8 75mm Howitzer Motor Carriage, and underwent tests in January 1943. The basic principle was sound, but in March 1943 the Armored Force rejected the open topped turret.

A third alternative was provided by the T21 Light Tank project. This was based on the T20 Medium Tank design, and was developed in the second half of 1942. It would have carried a 76mm gun but despite fairly thin armour the T21 was expected to weigh 24 (short) tons, and was rejected by the Armored Force, who wanted their light tanks to weight 20 (short) tons or less.

Development

By March 1943 all three of the possible light tank designs had been rejected. The Ordnance Committee suggested that work should begin on a new design. This would use a 75mm gun, the successful power-train of the M5A1 light tank but with updated suspension and a three man-turret. Weight was to be kept low by only providing thin armour, and the new tank was only expected to serve in the reconnaissance role.

The new T24 programme was officially approved on 29 April 1943. The new tank was designed by General Motors, with the Chrysler and Cadillac divisions taking the lead, supported by the Ordnance Department. The basic hull design came from Cadillac, as did the twin V8 engines. The vertical volute suspension of the M3 and M5 Light Tanks was rejected and a newer torsion bar suspension system, similar to the one used on the M18 Hellcat Tank Destroyer, was chosen.

The biggest problem was the weight of the standard 75mm guns. A solution was provided by the USAAF, which had developed a lightweight T13E1 75mm gun for use in the B-25 Mitchell. This used a concentric recoil mechanism that took up less space and reduced the distance of the recoil. The new gun was successfully tested in the summer of 1943.

In the meantime work on the T24 progressed quickly. A wooden mock-up was completed in May 1943 and was followed by two pilots. The first of the pilots was delivered in October, but the Ordnance Committee was so confident that in September 1943 they requested production of 1,000 tanks. The chief of engineers objected to the new design on the grounds that it was too wide (it was actually wider than the M4 Sherman), but he was overruled. The only condition that was imposed was that the M24 should replace the M5A1 on existing production lines.

The first pilot began tests at the Aberdeen Proving Ground in mid October 1943. The only significant issue was a problem with the concentric recoil system, but that was fixed on the second pilot, which began its trials in December 1943. At this stage the Armored Board asked for wet ammunition storage, a vision cupola for the command and a pistol port on the turret.

The T-24 was standardised as the M24 Light Tank in July 1944. It was named the Chaffee to honour General Adna Chaffee, the first head of the US Armored Force.

In December 1943 another 800 M-24s were ordered and eventually a total of 5,000 were ordered. Production at Cadillac began late in April 1944 and between then and July 1945 they built 3,592 M-24s. Massey-Harris also switched production from the M5A1 and built 1,139 M-24s between July 1944 and June 1945. Between them the two firms built 4,731 M-24s.

The 75mm gun used in the M24 could fire the same shells as the M4 Sherman, but the shorter barrel length meant that it produced lower muzzle speeds and less armour penetration. The new gun thus wasn't particularly effective against the German tanks of 1944-45, but that wasn’t really its purpose. The M24 wasn't expected to stand up and fight if it ran into German tanks, but instead to retreat and report what it had found. The big advantage of the 75mm gun was that was far more effective against German anti-tank guns or infantry strongpoints than the 37mm gun of the M5A1, which by 1944 was far too short ranged to be useful. The projectile in the standard high explosive shell used in the 37mm gun weighed 1.51lbs, the equivalent projective for the 75mm gun weighed 14.70lbs!

Description

The M24 had torsion bar suspension with five pairs of road wheels on each side, a raised rear idler and front drive wheel. The twin Cadillac engines were at the rear, and the transmission and final drive were at the front.

The M24 was considerably bigger than the M5, in every dimension. The M5 was 14ft 2.75in long, 7ft 4.25in wide and 7ft 6.5in high. The M24 was 18ft long, 9ft 4in wide and 8ft 4in tall. The sleeker design always seems to make the M24 look lower than the M5 so it comes as something of a surprise to discover that it was nearly 10in taller.

Because the M24 was a larger vehicle than the early tanks there was no need for sponsons above the top of the tracks (used for essential storage on the M3 and M5). The hull and superstructure formed a single armoured box. The sides were simple flat armoured sheets, but they sloped inwards, so the hull was wider at the top than at the bottom. This increased the amount of space available for the turret ring and also gave the tank slightly sloped side armour.

The front of the tank was pointed, with the lower plate more steeply sloped than the top plate. The top of the superstructure was made up of a series of flat plates that were all gently sloped to give the impression of a curve with the turret at the highest point.

From above the turret had a tear-drop shape, with a circular plan to the sides and front, but extended at the back to create some storage space within the turret. The turret had sloped sides - the bottom third sloped out from the ring, and the top two thirds then sloped back in towards the roof.

The 75mm gun was protected by a mantlet that was almost rectangular when seen from the front (but with a curved top), and curved when seen from the side. The .30in machine gun was mounted in the bottom right on the mantlet (as seen from the turret), and the .50in anti-aircraft gun was on a pedestal mount at the back of the turret. The commander's cupola was at the back left of the turret. The gunner was at the front left of the turret and the loader at the front right.

The driver sat in the front-left of the fuselage. There was a .30in machine gun built into the front right of the hull, and this was operated by the fifth member of the crew, who served as hull gunner, co-driver and radio operator.

The result was a tank that even today looks sleek and modern.

The M24 had a short post-war career in the US Army - in 1951 the M41 Walter Bulldog light tank entered service and the M24 was declared surplus and the surviving tanks were sold off.

Combat

Europe

The M24 began to reach the front line late in 1944, several months later that first planned. The original plan was to send 160 tanks to Europe in August, but the tanks weren't ready.

In November the army decided to use the first M24s to equip the two remaining light tank battalions, the 744th and 759th, then to move onto the light tank companies in the 2nd and 3rd Armoured Divisions.

The first tanks reached France by 8 December and set off for the 744th. Two of them were taken over by the 740th Tank Battalion, a unit that had arrived in Europe without any tanks and was now being sent to the Ardennes to help try and stop the German advance. They managed to acquire two of the twenty M24s in this first batch, and the new tank got its combat debut on 20 December 1944. They survived this fighting and remained in use with the 740th into January 1945.

The 744th received its first M24s on 24 December, and had completely re-equipped with the new tank by mid February. The M24 was then used during Operation Grenade, the crossing of the Roer River. The M24 performed well in this first large-scale battle, and its mobility, reliability and improved crew accommodation meant it was very popular with its crews. The thin armour was still seen as a problem and there wasn't enough ammo storage for the sort of battles being fought as the US Army advanced into Germany. The 744th continued to operate the M24 to the end of the war, but it did partly convert to the M4A3(76) Sherman before the end of the fighting.

The 759th didn't fully convert to the M24. Towards the end of the war in Europe one company did receive the M24, but the rest of the battalion had to struggle on with the M5A2.

The next units to receive the M24 in Europe were the light tank troops in the cavalry reconnaissance squadrons. They had been suffering badly with the M5 and received most of the first 200 M24s to reach Europe.

The biggest users of the M24 in Europe were the last four armoured divisions to reach Europe - the 8th, 13th, 16th and 20th. These had received the M24 in the United States and thus deployed with them.

Once the reconnaissance squadrons had received their M24s the priority went to the existing armoured divisions. The independent Tank Battalions received very few M24s. At the start of May 1945 there were 1,163 M24s in use in the European Theatre - 611 with armoured divisions, 455 with cavalry reconnaissance squadrons and only 97 with independent tank battalions.

The M24 was generally popular with its users. They praised its mobility and the 75mm gun was seen as a great improvement over the 37mm gun of the M5. The thin armour was acknowledged, but there was a general feeling that the M4 Sherman's armour was no more effective.

The M24's gun couldn't penetrate the armour of the Tiger or Panther at normal combat distances, but on occasions they did achieve victories over the larger German tanks. In early March two M24s from the 4th Cavalry Reconnaissance Squadron ran into two tanks reported to have been Tigers near Domagen. The faster moving M24s managed to hit the side and rear turret armour of the German tanks causing internal explosions that burnt out both tanks,

Italy

The Italian front had a lower priority, and so very few M24s found there way there. The main user was the 81st Cavalry Reconnaissance Squadron of the 1st Armoured Division, which used them from March 1945. The 13th Armoured Battalion, 1st Armoured Divison, also received a number of M24s.

The M24 didn't reach the Pacific before the end of the war. The Marine Corps did test out the type but didn't accept it for service. The US Army used the M24 during the occupation of Japan as the light tank was capable of travelling on Japanese bridges that were too light for the heavier M4 Sherman.

Export

The only significant overseas user of the M24 during the Second World War was Britain, where 302 were received. They were used to replace the Stuart light tank in a number of units, including the 5th Royal Inniskilling Dragoon Guards and the 8th Hussars, 7th Armoured Division. They were used in combat during the last phase of the war in Germany.

After the end of the war the M24 was exported to many American allies, including Australia, Austria, Belgium, Canada, Taiwan, Denmark, Ethiopia, France, Greece, Iran, Iraq, Italy, Japan, Laos, Netherlands, Norway, Pakistan, Philippines, South Korean, South Vietnam, Spain, Taiwan, Thailand, Turkey , Uruguay and UK

The French received the most M24s - over 1,000 eventually - and used it in Vietnam and during the Algerian War.

The South Vietnamese also used the M24 in combat, as did Pakistan during the 1965 and 1971 wars with India.

Korean War

The M24 was the only America tank in Japan at the start of the Korean War. There were four American divisions in Japan, each with their own light tank company.

The North Koreans were equipped with the T-34/85, and many of their troops were experienced veterans of the war in Europe or the Chinese Civil War. The T-34s helped the North Koreans overwhelm the South Korean army and they were soon streaming south across the country. The four M24 tank companies in Japan were quickly formed into a provisional tank battalion, with a total of fifth tanks, and were shipped to Korea. The war began on 24 June 1950, and the American tanks were in the country by early July.

On 7 July fourteen tanks from the battalion were sent north to support the 24th Division, which was fighting near Jeonju (Chonjui) on the Geum River. The 24th Division had been fighting further north, at Osan, but was forced to retreat towards the Geum. The first clash between the M24s and the T-34/85 came on 10 July just north of Geum. Neither side performed especially well during this clash. The M24 struggled to damage the T-34s, and most of their shots bounced. One T-34 was disabled. In return the North Koreans failed to knock out any of the Americans, but two M24s were lost after their gun recoil systems failed. The Americans were unable to hold the line of the river, and by 24 July the UN forces had been pushed back to the Pusan perimeter. A significant number of the M24s were lost during the retreat and the balance of power was only restored after the arrival of M4 Shermans and M26 Pershings in August. The M24 was used for reconnaissance during the rest of 1950, and by the end of the year 138 tanks had been sent to Korea. The M24 was eventually withdrawn to Japan, although the M19 Multiple Gun Carriage and M41 self propelled guns, both derived from the M24, remained in use.

Variants

The M24 was used as the basis for a number of self-propelled guns, sometimes known as the Light Combat Team. They used a modified M24 chassis with the engine in the middle and the fighting platform at the rear These included the M19 40mm Motor Gun Carriage, M41 155mm Howitzer Motor Carriage and a number of more experimental designs. It was also the basis for the T77 Multiple Gun Motor Carriage and the M37 105mm Howitzer Motor Carriage, both of which used a more standard M24 chassis. 

M19 40mm Gun Motor Carriage

The M19 carried twin 40mm Bofors anti-aircraft guns on a circular platform at the back of a M24 light combat team chassis. It arrived too late for combat in the Second World War, but was used as an infantry support weapon during the Korean war.

M37 105mm Howitzer Motor Carriage

The M37 105mm Howitzer Motor Carriage was produced to provide a lighter version of the M7 105mm Howitzer Motor Carriage 'Priest'. The M37 was used in the Korean War.

M41 Howitzer Motor Carriage

The M41 155mm Howitzer Motor Carriage carried a long barrelled howitzer on the M24 light combat team chassis. It was used during the Korean War.

T38 Mortar Motor carriage

The T38 Mortar Motor Carriage was a version of the M37 HMC but armed with a 4.2in mortar. It was cancelled at the end of the Second World War.

T77 Multiple Gun Motor Carriage

The T77 carried a quad .50in mount in a specially designed turret, which replaced the standard M24 turret. The T77 was developed between 1943 and 1945, and reached the trials stage during 1945 but it was abandoned after the end of the Second World War.

T78 90mm Gun Motor Project

The T78 was a project to mount a 90mm gun on the M24 chassis. Very little progress was made.

T81 Multiple Gun Motor Carriage

The T81 was a design for a vehicle with a single 40mm and twin .50in calibre anti-aircraft guns, on the M24 chassis

T96 155mm Mortar Motor Carriage

The T96 155mm Mortar Motor Carriage was a design for a vehicle that would have carried a 155mm T37 mortar on the M24 chassis.

Stats
Production: 4,731
Hull Length: 18ft
Hull Width: 9ft 4in
Height: 8ft 4in
Crew: 5 (commander, gunner, loader, driver, co-driver/ radio operator/ hull gunner)
Weight: 40,500lb
Engine: 220hp Twin Cadillac 44T24 petrol engine
Max Speed: 35mph (road), 25mph (cross-country)
Max Range: 100 miles road radius
Armament: 75mm M6 gun, two .30in machine guns, one .50in anti-aircraft machine gun
Armour: 9-25mm

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How to cite this article: Rickard, J (4 July 2014), M24 Light Tank Chaffee , http://www.historyofwar.org/articles/weapons_M24_light_tank_chaffee.html

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